Cyclopentadienyl nickel triorganophosphine halides



composition.

United rates i atent 3,054,315 CYCLOPENTADIENYL NICKEL TRIGRGANU- PHOSPEWE HALIDES Gene E. Schroll, Baton Rouge, La, assignor to Ethyl Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 25, 1960, Ser. No. 71,416 4 Claims. (Cl. 260-439) This invention relates to new nickel compounds and more especially to a novel group of cyclopentadienyl nickel compounds and a method for their preparation.

Up to this time there have been several nickel compounds which could be thermally decomposed to yield extremely pure metallic nickel powder. One such compound, nickel tetracarbonyl, has proven to be excellent in yieldingly highly pure nickel powder upon thermal de There is, however, one definite drawback in that nickel tetracarbonyl is so volatile that there is a necessity of providing stringent safety features to protect operating personnel against exposure to its vapors. Thus, although nickel carbonyl can be decomposed thermally at relatively low. temperatures (e.g., 53 C.) to give the pure nickel powder, its high volatility is a handicap. Other compounds, e.g., cyclopentadienyl nickel nitrosyl and biscyclopentadienyl nickel can also be thermally decomposed to yield the metallic nickel powder but in this case the thermal decomposition temperatures are higher than would be desired in this metallurgical application. in general, the cyclopentadienyl metal compounds are characterized by high thermal stability. Consequently, a need exists for nickel compounds having relatively low volatilities and having relatively low thermal decomposition temperatures so that they could be effectively and efiiciently used in the manufacture of nickel powders.

Accordingly it is an object of this invention to fulfill this need. Another object is to provide a new class of nickel compounds. It is a further object to provide a new organo nickel compounds of relatively low volatility which can be thermally decomposed at relatively low temperatures to yield metallic nickel powder. It is still a further object of this invention to provide a process by which these organo nickel compounds can be produced. Other objects of this invention will be obvious from the discussion which follows.

It has now been found that these and other objects are accomplished by the provision of cyclopentadienyl nickel triorganophosphine halide compounds. More particularly, these compounds are cyclopentadienyl nickel triorganophosphine halides having the formula wherein R is a cyclopentadienyl hydrocarbon radical which contains from 5 to about 12 carbon atoms. R is a hydrocarbon radical containing up to about 12 carbon atoms and is selected from the group consisting of alkyl or aryl radicals and X is a halogen selected from the group consisting of chlorine, bromine and iodine. A preferred embodiment of this invention is cyclopentadienyl nickel triarylphosphine halides while the most preferred embodiment of this invention is cyclopentadienyl nickel triphenylphosphine chloride. These compounds are preferred because of their simplicity of preparation and because of the availability of raw materials for their preparation.

Typical examples of the compounds which form a part of the present invention are cyclopentadienyl nickel triphenylphosphine chloride, cyclopentadienyl nickel trimethyl phosphine chloride, cyclopentadienyl nickel triethylpho-sphine chloride, cyclopentadienyl nickel triisobutylphosphine chloride, cyclopentadienyl nickel triethylphosphine iodide, cyclopentadienyl nickel triphenylphos- 3,5i,3l5 Patented ent. 18, 1962 ll QC phine bromide, cyclopentadienyl nickel tri(m-tolyl)phosphine iodide, cyclopentadienyl nickel tri(p-tolyl)phosphine bromide, methylcyclopentadienyl nickel triphenylphosphine chloride, ethylcyclopentadienyl nickel triethylphosphine bromide, methyl-tert-butylcyclopentadienyl nickel trioctylphosphine chloride, indenyl nickel triphenylphosphine chloride, and the like.

These cyclopentadienyl nickel triorganophosphine halides fit the need for organometallic compounds which can readily be thermally decomposed into relatively pure metallic powder. The nickel compounds of this invention are not nearly as volatile as nickel carbonyl, thus cutting the handling problems presented by the latter compound to the Very minimum. On the other hand, these compounds decompose at a relatively low temperature, thus disposing of the need for a great amount of heat as required by other nickel compounds, even other cyclopentadienyl nickel compounds.

Another embodiment of the present invention is the process for producing cyclopentadienyl nickel triorganophosphine halides comprising reacting a bis(tri0rganophosphine) nickel halide with a bis-cyclopentadienyl nickel compound in an inert anhydrous solvent. The bis(trior ganophosphine) nickel is characterized in that the organo groups each contain up to about 12 carbon atoms and the said organo groups are alkyl or aryl. The halide of the bis(triorganophosphine) nickel halide is selected from the group consisting of chlorine, bromine or iodine. The bis-cyclopentadienyl nickel compound is characterized in that the cyclopentadienyl groups are hydrocarbon radicals, each containing from about 5 to about 12 carbon atoms. The reaction temperature of this process involves a temperature of from about 0 C. to about 200 C. sufficient to eifect such reaction.

Suitable inert solvents for the practice of this invention comprise ethers (including polyethers) and aromatic hydrocarbons.

A preferred process of this invention comprises reacting a bis(triarylphosphine) nickel halide with a bis-cyclopentadienyl nickel compound in an ether solvent at a temperature of from about 0 C. to about 200 C. sufficient to effect the reaction. The product obtained from this preferred process is a cyclopentadienyl nickel triarylphosphine halide compound. The most preferred process of this invention comprises reacting bis(triphenylphosphine) nickel chloride with bis-cyclopentadienyl nickel in tetrahydrofuran at a temperature in the range of about 0 C. to about 200 C. suflicient to effect such reaction. The product obtained from this most preferred process is cyclopentadienyl nickel triphenylphosphine chloride.

During the above described reactions, the reaction system should be kept anhydrous and care should be taken to prevent air or oxygen from entering the system. Thus it is highly desirable to conduct the process under an inert atmosphere such as dry nitrogen, argon, neon, krypton, gaseous paraflinic hydrocarbons, or the like.

Although the temperature at which the process of this invention can be run ranges from about 0 C. to about 200 C., the more preferred temperature range is from about 20 C. to about C. However, at temperatures of above 35 C. the rate of the reaction takes place at a much faster rate.

The time required for the reaction to go to completion depends on the conditions under which the reaction is conducted, especially temperatures and solvents used. Times between a few minutes and several hours are generally quite adequate. It is usually preferred, however, to conduct the reaction for a period of from about 15 minutes to about 10 hours.

The preparation of the starting materials constitutes a most important step in both successfully completing the process and making the compounds of this invention. In order to obtain the bis(triorganophosphine) nickel halide reactant one must react an anhydrous nickel halide in an anhydrous alcohol with a triorganophosphine in the absence of air at the reflux temperature of the system. The bis(triorganophosphine) nickel halide compound so formed is then washed after which it can be reacted with the biscyclopentadienyl nickel compound to give the compounds of this invention. It must be noted here that the nickel halide must be anhydrous and the whole process of making the starting materials must be conducted in the absence of air and water.

This invention will be still further understood by reference to the following examples. In these examples all parts and percentages are by weight.

Example I Anhydrous nickel chloride (25.9 parts) was reacted with triphenylphosphine (105 parts) in 1600 parts of nbutanol and the mixture was refluxed for 4 hours. The reactants were cooled to 25 C. and the product, bis(triphenylphosphine) nickel chloride was filtered off and washed with benzene and hexane.

The complex salt, bis(triphenylphosphine) nickel chloride (26.5 parts) was placed in 350 parts of tetrahydrofuran with 26.5 parts of bis-cyclopentadienyl nickel and the mixture was heated under reflux conditions for 6 hours in a nitrogen atmosphere. The tetrahydrofuran solvent was distilled off, benzene was added to the residue and the resultant mixture was filtered to eliminate the impurities. The filtrate was concentrated to 40 ml. and hexane was added in excess to the hot concentrate to precipitate a bright red solid. The solid, cyclopentadienyl nickel triphenylphosphine chloride, was washed with hexane and pumped free of the solvent. The desired product, cyclopentadienyl nickel triphenylphosphjne chloride was obtained in 88 percent yield. It decomposes without melting at about 140 C.

Analysis.-Calcd. for C H ClNiP: C, 65.7; H, 4.8; Ni, 13.9; C1, 8.4; molecular weight, 422. Found: C, 65.6; H, 5.5; Ni, 13.9; Cl, 8.4; molecular weight, 448.

Example II Anhydrous nickel bromide (62.5 parts) is reacted with tri-n-butylphosphine (115.6 parts) in n-butanol in the same manner as Example I to give the starting material, bis(tri-n-butylphosphine) nickel bromide.

Bis(tri-n-butylphosphine) nickel bromide (89 parts) is reacted with 31 parts of bis(methylcylclopentadienyl) nickel for 4 hours in 180 parts of 1,2-dimethoxy ethane at the reflux temperature of the system in an argon atmosphere. The product, methylcyclopentadienyl nickel tri-nbutylphosphine bromide is recovered in the same manner as set forth in Example I.

Example Ill The starting material, bis(tri-n-butylphosphine) nickel iodide is made by the reaction of anhydrous nickel iodide and tri-n-butylphosphine in the same manner as set forth in Example I. Bis(tri-n-butylphosphine) nickel iodide (72 parts) is reacted with 29 parts of bis-indenyl nickel for 7 hours in 216 parts of bis(2-methoxy ethyl) ether at 50 C. in a nitrogen atmosphere. The product, indenyl nickel tri-n-butylphosphine iodide, is recovered in the same manner as set forth in Example I.

Example IV Tri-m-tolylphosphine (37.6 parts) is reacted with 8 parts of anhydrous nickel chloride in 480 parts of nbutanol at reflux temperature for 4 hours. The product, bis(tri-m-tolylphosphine) nickel chloride, is isolated in the manner set forth in Example I.

Bis(tri-m-tolylphosphine) nickel chloride (34 parts) is reacted with 10 parts bis(methylcyclopentadienyl) nickel in 140 parts of n-butyl ether at 100 C. for 8 hours in a neon atmosphere. The solvent is evaporated under vac- Ziuum and the product is crystallized from a benzenehexane mixture to give methylcyclopentadienyl nickel trim-tolylphosphine chloride.

Example V Tri-n-decylphosphine (629 parts) is reacted with anhydrous nickel bromide (151 parts) and 6,000 parts of nbutanol. This mixture is heated at the reflux temperature of the system for 8 hours in a nitrogen atmosphere and the product, bis(tri-n-decylphosphine) nickel bromide is isolated in the same manner as set forth in Example I.

Bis(tri-n-decylphosphine) nickel bromide (390 parts) is then reacted with bis(indenyl) nickel parts) in 1500 parts of toluene. This mixture is heated at the reflux temperature of the system for 20 hours. The product, indenyl nickel tri-n-decylphosphine bromide, is recovered in the same manner as set forth in Example I.

It is to be noted that the compositions of matter of this invention may be exposed to the atmosphere for short periods of time without significant decomposition. However, during the preparation of these products, oxygen and water should be excluded. The products may be crystallized from a benzene-hexane mixture in order to remove trace impurities.

The proportions of the reactants used in this process can be varied. However, in order to secure the desired product in pure form and in highest yield, it is advantageous to use one mole of the bis-cyclopentadienyl nickel derivative to one mole of the bis (phosphine) nickel halide complex (ratio 1:1). If a significant excess of the halide complex is used, the conversion to the desired product is reduced somewhat by side reactions giving insoluble salts. On the other hand, if a significant excess of hiscyclopentadienyl nickel is used it is somewhat difiicult to separate the desired product from this reactant. Generally speaking, the mole ratio of bis-cyclopentadienyl nickel compound to the nickel halide complex should therefore range from about 2:1 to about 1:2.

The inert solvents which are used in this process can be aromatic hydrocarbons or ethers. The more particularly preferred solvents, however, are ethers with lower boiling points because of their great solubilizing action and their ease of removal from the end product. Typical examples of suitable inert solvents are tetrahydrofuran, 1,2-dimetha oxyethane, bis(2-methoxyethyl)ether, n-butylether, anisole, diphenylether, 1,2-diethoxyethane, ethylether, benzene, xylene, 1,2,3,4-tetrahydronaphthalene, dioxane, furan, toluene, dimethoxybenzene, ethylbenzene, n-propylbenzene, n-butylbenzene, naphthalene, biphenyl, butylphenyl ether, methylethyl ether, butylpropyl ether, and the like.

The uses for the unique compounds of this invention are varied and many in number. Besides being especially adapted for use in making nickel powder, they have utility as antiknock compounds when blended with petroleum hydrocarbon mixtures suitable for use in spark ignition internal combustion engines. These compounds also may be used as plating agents in vapor phase plating processes. They may also be used as antioxidants in various types of oils and they may be used as catalysts in polymerization processes. Another use for the compounds of this invention is in the field of agriculture for use as herbicides, fungicides, and the like.

Having thus described the compositions of matter and processes for making them, it is not intended that this invention be limited except as set forth in the following claims.

What is claimed is:

1. As a new composition of matter, cyclopentadienyl nickel triorganophosphine halides having the formula R'NiPR X wherein R is a cyclopentadienyl hydrocarbon radical which contains from 5 to about 12 carbon atoms, R is a hydrocarbon radical containing up to about 12. carbon atoms and is selected from the group consisting of alkyl and aryl radicals, and X is a halogen selected from the group consisting of chlorine, bromine and iodine.

2. Cyclopentadienyl nickel triphenylphosphine chloride.

3. A process for producing cyclopentadienyl nickel triorganophosphine halides comprising reacting a his- (triorganophosphine) nickel halide with a bis-cyclopentadienyl nickel compound in an inert anhydrous solvent and under an inert. atmosphere; said bis(triorganophosphine) nickel halide being characterized in that the organo groups thereof each contain up to about 12 carbon atoms and are selected from the group consisting of alkyl and aryl, and in that the halide atom thereof is selected from the group consisting of chlorine, bromine and iodine; said bis-cyclopentadienyl nickel compound being characterized in that the cyclopentadienyl groups thereof are hydrocarbon cyclopentadienyl radicals each containing from 5 to about 6 12 carbon atoms; said reaction being run at a temperature of from about 0 C. to about 200 C. sufiicient to elfect such reaction.

4. A process for producing cyclopentadienyl nickel triphenylphosphine chloride comprising reacting bis(triphenylphosphine) nickel chloride with bis-cyclopentadienyl nickel in tetrahydrofuran and an inert atmosphere at a temperature of from about 0 C. to about 200 C. sulficient to effect such reaction.

References Cited in the file of this patent Wilkinson et al.: J. Inorganic and Nuclear Chemistry, vol. 2, January 1956, pages 32-37.

Venanzi: Journ. of the Chem. Soc., February 1958, pages 719-724.

Cotton et al.: Nature, April 16, 1960, vol. 186, pages 233234. 

1. AS A NEW COMPOSITION OF MATTER, CYCLOPENTADIENYL NICKEL TRIORGANOPHOSPHINE HALIDES HAVING THE FORMULA 